REMEDIAL DESIGN CONCEPT FOR BOLIVAR DAM

Due to a history of excessive through- and under-seepage during events with frequent return periods, a major rehabilitation study was undertaken for Bolivar Dam. In addition to traditional deterministic analyses, probabilistic seepage and slope stability analyses were completed to address uncertainty regarding project conditions, and to guide the selection of a remedy that effectively reduces the risk of unsatisfactory performance for foreseeable loadings. Analyses consisted of calculating expected factors of safety against erosion across the projected load range, using finite element models calibrated to past field data and observations. Modeling was then completed using ranges of input parameters for key variables, and results were combined to yield probabilities that the expected factors of safety were less than unity for all base and proposed rehabilitation load cases. Based on results, the current remedy design concept for addressing Bolivar Dam’s seepage and slope stability deficiencies includes the construction of a partial-depth seepage barrier, the augmentation of an existing downstream seepage blanket, and the preventative maintenance and/or rehabilitation of existing relief wells as necessary to maintain efficiency.